Switching arrangement for an electric motor



Feb. 10, 1959 R. G. GRIFFITH SWITCHING ARRANGEMENT FOR AN ELECTRIC MOTOR 2 Sheets-Sheet 1 Filed May 2, 1955 A rTa/ews vs Feb. 10, 1959 R. G. GRIFFITH SWITCHING ARRANGEMENT FOR AN ELECTRIC MOTOR Filed May 2, 1955 2 Sheets-Sheet 2 //v VE/VTOR fiorvmca 56k?! TH A r TOR/VEYS United I States SWITCHING ARRANGEMENT FOR AN ELECTRIC MOTOR Ronald G. Griflith, Montreal, Quebec, Canada Application May 2, 1955, Serial No. 505,481 Claims priority, application Great Britain May 3, 1954 13 Claims. (Cl. int-4.1

The present invention relates to an automatic starting and stopping mechanism for an electric motor to be used particularly with telegraph type printing apparatus.

The construction of such a telegraph printing apparatus is considerably simplified in accordance with the present invention by the provision of a single bail which is arranged to effect all the ancillary functional operations for switching the motor off. i

The present invention consists of a switching arrangement for an electric motor which comprises mechanism for switching off the motor. The mechanism is actuated by a single cam operated bail co-acting with a pivoted pawl member. The cam is driven by the motor.

According to a preferred arrangement, the switching mechanism is spring biased to the on position. A spring biased pivoted cradle is adapted to lock the mechanism in the off position. A second pivoted cradle may be pro vided which is adapted to trip the first pivoted cradle to thus release the switching mechanism.

According to a preferred embodiment of the invention, a signal actuated magnet is provided which is arranged to effect the release of the switching mechanism by tripping one of the pivoted cradles. There may also be provided a manually operated on lever adapted to mechanically actuate one of the pivoted cradles. A second manually operated lever may be provided which is adapted to mechanically condition a second pawl for co-action with the single operating bail to effect the switch- 'ing off of the motor.

According to the preferred form of the invention, a pivoted pawl member is conditioned for co-action with the operating pawl by a predetermined co-setting combination of a number of permutation members.

The present invention also provides a counting mechanism which is driven by the motor. The counting mechanism is adapted to switch off the motor, after a predetermined count, by conditioning a pivoted pawl for coaction with the operating bail. The pivoted pawl is adapted to actuate the switching mechanism. The counting mechanism may be adapted to be reset to a zero position each time the switching mechanism is moved to the on position.

A preferred embodiment of the invention is illustrated in the accompanying drawings in which:

Fig. l is a partly sectional pictorial view of part of the switching arrangement,

Fig. 2 is 'a partly sectional pictorial view of part of the switching arrangement, and is a continuation of'Fig.

Fig. 1 and Fig. 2 together form the complete switching arrangement, the parts 142, 156, 157, 185, 186 and 187 being shown in both figures and showing how the two figures are connected.

Referring firstof all to Figure 1, an electric motor M for driving the teleprinter is supplied, by a source V, with current which passes through a micro-switch 146 having terminals 147 and 148. The switch 146 is con- .trolled by a bellcrank lever 149 which is biased by a ice spring 202 in a clockwise direction to tend to keep the switch in the on position (as shown). When the lever 149 is moved against the bias in an anti-clockwise direction by the clockwise movement of either of two members 168 and 191, it is held in this anti-clockwise off position by a latch in the form of a cradle 150. In order subsequently to switch on the motor, this cradle 150 is turned about its pivotal axis 261 in an anti-clockwise direction by the engagement between a detent 156, on a trip cradle 142, and an extension 157 of the cradle 150 itself.

Switching on the motor is therefore effected by movement, in an anti-clockwise direction, of the cradle 142, which is seen in full in Figure 2. This cradle is formed with a detent 141 which, when the teleprinter is inactive, engages a cam 161 on the selecting cam shaft, shown at 140, of the teleprinter. The cradle 142 is acted upon by a spring 143 tending to turn it in a clockwise direction to disengage the detent 141 and the cam 161, but such turning is prevented by the engagement of a detent 160, of a pawl 144 pivoted on the cradle 142, with a stop-plate 145 which constitutes part of the frame of the switching arrangement. The. detent 160 is kept in firm engagement with the plate 145 by a spring 211. If the lower end of the pawl 144 is moved to the left to disengage the detent 160 and the plate 145, the cradle 142 is pulled in a clockwise direction by the spring 143. As previously described, this causes switching on of the motor, which then drives frictionally the cam shaft 140, which turns anti-clockwise. During this turning, a re-set cam 158, also mounted on the cam shaft 140, acts on a detent 159 of the cradle 142m. turn the latter into its anti-clockwise. position in which the detent 141 lies in the path of the cam 161. Thus after half a revolution of the shaft 140, the cam 161 engages the detent 141 and the shaft stops, while at the same time, the detent 160 reengages with the plate to latch the cradle 142 in position. During the anti-clockwise movement of this cradle 142, the spring 143 becomes extended and thus stores energy, provided by the motor M itself, and it is this energy which serves on'subsequent release on the pawl 144 to switch on the motor, as will appear later.

The movement to the left of the lower end of the pawl 144 to release the teleprinter for a complete cycle of operation is effected either by a normal receiving magnet 144a which receives incoming signals and acts then to pull the pawl 144 in an anti-clockwise direction, or by means of a lever 155. The latter can be actuated by a manually operated on key 152 which is normally held against an upper stop 163 by means of a spring 203 but which, on being depressed towards a lower stop 164, engages a cradle 153. This cradle 153 turns about an axis 154 and moves the lever 155 to engage a projection 162 on the lower end of the pawl 144 and move it to the left to release the pawl 144. As can be seen, the lever 155 is not integral with cradle 153 but is connected to it through a pivot and a spring so that if the on key 152 is held depressed, the cam shaft 146) does not rotate continuously. In fact, if the key 152 is held depressed, the projection 16?. is first moved to the left by the lever 155 and is then moved downwardly by clockwise movement of the cradle 142, out of alignment with the lever 155. The latter is then lifted by the projection 162 as the detent and the plate 145 re-engage on anti-clockwise movement of the cradle 142.

When once started, either by pressing the 'key 152 or on receipt of an incoming signal by the magnet 144a, the motor M may be stopped in one of three ways, each of which relies, however, on the movement of a bail 76 (see Figure 1) which is movedin a clockwise direction by a cam 79 each time that the teleprinter is released for a cycle of operation on the'rclease of the earn 161 by the detent 141. The cam 79 which brings about this movement of the bail 76 is carried by the operating cam shaft, shown at 212, which is driven by the motor M through a clutch mechanism which is released forhalf a revolution during each half revolution of the selecting cam shaft 140. Thus for each half revolution of this selecting cam shaft 140, the bail 76 rocks to and fro. Under conditions where signal combinations are being received continuously, this movement of the bail has no efiect and the motor M continues to operate.

wise movement of the member 168 or 191 and the anticlockwise movement of the bell-crank lever 149, which opens the switch and this stops the motor.

Lowering of the pawl 167 is eifected by .a number of mechanical elements or vanes V1, V2, V3, Vd, V2.7 and V5, each of which can rock between two extreme positions about its own pivot shaft 165. The positioning of "the elements is effected in accordance with received signal character combinations by a mechanism as disclosed in my copending application Serial No. 505,479, filed May 2, 1955. See also British Patent 777,719. On receipt of a predetermined combination, the resultant setting of the elements allows a notched bar 166, supporting the pawl 167, to drop. On subsequent'movement of the bail 76, this pawl 167 is moved to the right and switches off the motor M. Subsequent anti-clockwise movement of the bail 76 to release the pawl 167 is accompanied by upward movement of a reset bail 215 having a cam follower 214 controlled by a cam 213 mounted on the operating cam shaft 212.

Lowering of the pawl 187 against a spring 188 is effected through a spring extension 186 by the movement to the right of an extension 185 of a cradle 184 (see Figure 2). Such movement of the cradle 184 may be effected by engagement with it of an extension 194 of a cradle 204 connected to a manually operated 011" key 193. Depression of the key 193 causes the extension 194 to move upwards to turn the cradle 184 in an anticlockwise direction, so that the extension 185 moves to the right (Figure 2). This causes the extension 186 to be pressed downwardly and this causes the pawl 187 also to move downwards, into the path of the bail 76. During the movement of the cradle 184, caused by depression of the key 193, the extension 189 engages the cradle 190 to turn the latter in a clockwise direction so that the extension at the right hand end of the cradle 19% moves upwards. This extension engages the cradle 153 and turns it just as if the on key 152 has been depressed. As a consequence, the shaft 140 is released for a half revolution and this represents a complete, cycle of operation such as is necessary to record a signal code combination received by the teieprintcr.

Movement of the'cradle 184 to cause stopping of the motor can also be effected by a delay device controlled by the motor and operating after a predetermined time delay following receipt by the teleprinter or the last signal character combination. This delay device is shown in Figure 2 and includes an eccentric cam 169 mounted on the main shaft of the motor M so as to rotate whenever the motor moves. A cam follower 1'70, engaging the cam 169 so as to oscillate backwards and forwards as the cam 169 rotates, is provided with two pawl teeth 171 and 172 for engagement respectively with two ratchet wheels 173 and 17 1, both mounted freely on a shaft 175. The ratchet wheel 173 is rotated in a clockwise direction ;-step.by step for each revolution of the cam 169, and on being advanced by one step is held in position by a retention lever 7'6. The wheel 173 has one notch .177 of greater depth than the other notches between teeth, so

d that once every revolution of the wheel 173, the tooth 171 approaches more closely to the shaft 175. During this movement, the tooth 1'72 engages the wheel 174 and the Wheels 173 and 174 then move one step together. On being advanced by one step, the wheel 174 is retained in position by a retaining lever 179. it will be realised that after a predetermined number of rotations of the cam 169, a striker pin 183 carried by the wheel 174 will engage the cradle 134 to turn it in an anti-clockwise direction. This causes lowering of the pawl 187 into the path of movement of the bail 76 and the latter is caused to operate by the release of the .teleprinter for one cycle, such release being brought about by the engagement between an extension 1&9 on the cradle 184 and a further cradle 19% which engages the cradle 153 to bring about release of the selecting cam shaft as previously described.

lf, before engagement between the pin 183 and'the cradle 184, a signal character combination is received by the teleprinter, a reset lever rants given an oscillation by coaction with a cam (not shown) carried on either the selecting cam shaft 140 or the operating cam shaft 212. This oscillation of the lever causes anti-clockwise movement of the lever 179 to release the wheel 174'which is then pulled round in an anti-clockwise direction by a spring 1715. As the lever 179 turns in an anti-clockwise direction, a latch 181 is pulled in an anti-clockwisedirection by a spring 2136 and this latch latches the lever 179 out of engagement with the wheel 174. As this wheel 174 reaches 'a zero position, however, a pin 182 which it carries engages the latch 181 to cause unlatchingof the lever 179 which then re-engages the wheel 174. The delay device is thus returned to its zero position whenever a signal combination is received, but acts after a time delay to stop the motor M in the absence of such combinations.

The wheel 174- is provided with a number of holes 192 into which the pin 183 can be inserted, so that the time delay before the motor is switched off can be adjusted.

What I claim a my invention is:

1. In a teleprinter, the combination of an electric motor for driving said teleprinter, a switch for switching said motor on and 011, a bail, means driven by said motor to oscillate said bail through a complete cycle during a complete cycle of operation necessary to record a signal code combination received by said teleprinter, means for opening said switch by the operation of said bail comprising a member movable between an inactive-position free of said bail and active position to be operated by said bail and thereby to switch off said motor, a delay device controlled by said motor and being operative, after a predetermined time delay following receipt by the teleprinter of the last signal combination, both to move said member into said active position and to initiate said complete printing cycle of operation, means for storing-energy derived from said motor, and means rendered operative onsubsequent receipt of an incoming signal by said teleprinter to effect closing of said switch bysaid stored energy.

2. A combination according to claim 1, and also comprising a number of permutation elements responsive in position to incoming signal character combinations, means including a second member movable'between inactive and active positions in relation to said bail and being operative to switch off said motor on movement of said bail when said second member is in said active position, and means controlled by said permutation elements for moving said second member into said active position for a particular setting of said elements on receipt of a predetermined combination.

3. A combination according to claim 2, and'also comprising a manually operated ofFkey connected to move said second member into said active position.

4. A combination according to claim "3, and also 'comprising a manually operated on key acting to release said stored energy means and switch on said motor.

5. A combination according to claim 1, and also comprising a manually operated on key acting to release said stored energy means and switch on said motor.

6. A combination according to claim 2, and also comprising a manually operated on key acting to release said stored energy means and switch on said motor.

7. A combination according to claim 1, and also comprising a mechanical piece for opening said switch and movable between inactive and active positions in relation to said bail so that said motor is switched ofi by said piece of movement of said bail only when said piece is in said active position, and a manually operated o key connected to move said piece into said active position.

8. A combination according to claim 7, and also comprising a manually operated on key acting to release said stored energy means and switch on said motor.

9. A combination according to claim 7, said piece being constituted by said member.

10. A combination according to claim 1, and also comprising resilient means for biasing said switch to the on position, a latch for holding this switch in the oil? position, and means responsive to the initiation of a complete cycle of operation of the teleprinter to move said latch to release said switch.

11. A combination according to claim 10, said means responsive to said initiation being in the form of a pivoted cradle.

12. In a teleprinter, the combination of an electric motor for driving said teleprinter, a switch for switching said motor onand off, a bail, means driven by said motor to oscillate said bail through a complete cycle during a complete cycle of operation necessary to record a signal code combination received by said teleprinter, means for opening said switch by theoperation of said bail comprising a member movable between an inactive position free of said bail and active position to be operated by said bail and thereby to switch off said motor, a delay device controlled by said motor and being operative, after a predetermined time delay following receipt by the teleprinter of the last signal combination, both to move said member into said active position and to initiate said complete printing cycle of operation.

' 13. In a teleprinter, the combination comprising an electric motor, a bail oscillated by said motor during a complete cycle of operation of said teleprinter, an electric circuit for supplying said motor with current, a switch in said circuit, a switch member biased to close said switch, a plurality of switching-01f members arranged to actuate said switch member and each having a pawl to be engaged by said bail, and a plurality of devices arranged to move respective switching-off members into and out of the path of movement of said bail whereby said motor switches itself ofi by means of any one of said devices.

References Cited in the file of this patent UNITED STATES PATENTS 1,821,165 Kleinschmidt Sept. 1, 1931 1,938,597 Krum Dec. 12, 1933 2,112,773 Griflith Mar. 29. 1938 2,640,873 Moebius June 2, 1953 2,672,501 Swan Mar. 16, 1954 FOREIGN PATENTS 817,612 Germany Oct. 18, 1951 

